Mold and method for making castings



Jan. 8, 1924. 1,480,191

T. E. F. WILSON MOLD AND METHOD FOR MAKING CASTINGS Filed 'Ju1y'l2 1920 MAG/V5 7/6} S LOCK/N6 OEWCE Patented Jan. 8, 1924.

UITED STATES PATENT OFFICE.-

THOMAS E. P. WILSON, F LYNN, MASSACHUSETTS.

MOLD AND METHOD FOR MAKING CASTINGS.

Application filed July 12, 1920. Serial No. 395,631.

wealth of Massachusetts, has invented an Improvement in Molds and Methods for Making Castings, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to molds and methods for casting metals and other substances and its object is to provide an improved mold and method having, among others, the

advantages hereinafter pointed out.

It is well known to those familiar with the art that great difficulty is experienced in making hard castings, such as steel, of irregular shape. If a steel or other non-yielding chill mold is used, the casting, while shrinking as it cools, is likely to crack whereverthe outline of the mold interferes with the free shrinking of the casting. This usually results in an injury to the casting, and some times to a degree which is fatal.

The foregoing difiiculty has resulted in the practice of using at times molds made of sand or other fine comminuted material which may be packed sufiiciently firm to fashion the casting, and yet yield slightly where necessary when the casting begins to cool and shrink, or in other words accommodate itself to any movement of the casting and thus prevent its cracking. This type of mold avoids the first difliculty, but a sand mold does not give a chill to the casting which is required for cutting tools and other purposes, and the mold is of course d estroyed each time by use. This results in great expense both of labor and time. My invention overcomes the difliculties above mentioned and makes possible the casting of steel and other metals in a chill mold.

In the drawing of one embodiment of my invention selected for illustration and description,

' Fig. 1 is a side elevation, showing also the gate on top of'the mold;

Fig. 2, a plan thereof;

Fig. 3, a plan of the mold proper with the gate removed; and

Fig. 4, a vertical section on the line 4-& vFig. 2, showing the interior of the mold and outline of the casting.

In this instance the mold is for casting a hammer head, and referring to Figs. 1, 3, the mold 1 is shown divided vertically along the lines 33 and 4-4:,ISlllti11g in the for v mation of substantially triangular or wedge shaped mold parts 2.

The portion of the mold chamber corresponding to the small or riveting head is marked 3, the body 4:, neck between the head jand body 5, large or hammer head 6, and neck between the body and large head 7 It will be clear that when the casting in such a mold is chilled or begins to cool, the

10, 11, will act to prevent free, natural longitudinal shrinking of the casting at those points,'and the casting accordingly will be either distorted in outline or cracked at or near these neck or narrowed sections.

If now the mold parts carrying these convex surfaces be free to move slightly at the instant the casting is chilled, the casting can-move naturally, as may be necessary,

inwardly or convex curved mold faces 8, .9,

and retain its proper outline and perfectness.

To that end I have conceived the novel lan of first properly dividing the mold into parts and then holding or looking the several mold parts together by any suitable means. For quick results and convenience, I prefer to use electro-magnetism, the current being turned on before the metal is poured, thus firmly locking the parts, and then turned off and the mold de-magnetized at the instant of chilling the casting, leaving each mold part free to move under pressure from the casting. The mold may be made of iron or any suitable material that will stand the heat of the casting and is suscepti ble of being magnetized. I

Accordingly when the casting shrinks if the heads 3 and 6 are drawn slightly toward I the body 4, the pressure on the convex neck surfaces 8, 9, 10, 11, will force the wedge shaped mold parts slightly apart radially and the casting will cool without being distorted or injured.

As stated, any suitable means may be used for the purpose of cont-rolling the movement of the mold parts, but in the present instance I have shown the mold as positioned upon a conventional magnetic surface. chuck 12. It will be obvious that any other device or construction may beused as well as a chuck,

so long as it is capable of being magnetized and is of sufficient area and outline to support the particular mold. ,v Themold having been so constructed and divided as to make the parts movable, it is assembled upon the magnetizing base, the gate 13 is positioned on the mold and the mold is then magnetized sutiiciently to hold the parts and gate all firmly together. F or this purpose it is of course necessary that the faces of the several mold parts be carefully machined and polished to fit closely each other. he hot metal is poured into the mold through the gate until the mold is filled, and men, a'tthe proper, instant, the operator deniagnetiaes the mold by turning off the current. As the casting cools and contracts, the several parts of the 'mold will yield wherever an-a to the extent necessary to permit the casting to. cool as a whole withoutc ra'ck'ing or straining any portion of the same-.; 7 J t V i If desirable for any reason,either for conv-cnience or economy oftime or material, the mold may be fashioned of a' y granular or finely comminuted material susceptible of being magnetized, such as iron or steel filings or crushediron or'e with a binder if necessary of-suitable material, as clay or molasses, Thism'aterial may be firmly fashioned in a flask or other suitable receptacle and then the hole mass, magnetized as before, thus holding the mold together until after the casting has been poured, when it will be demagnetized. In such a case the articles of material constituting the mold will'yield under the pressure of the contracting casting and the desired result obtained, the particles of material correspondingto the several mold parts in the present instance. I

if :desirable the inner face of the mold may be copper surfacedor otherwise prepared with any materialor substance which will neutralize any. tendency of the material of thecasting to adhere to the face of themold and. destroy the same.

- Of course the particular form of mold illustrated is .a. very simple. one and most convenient for the present purpose, but it will be clear that, by any invention, castings of very irregular outline can be successfully made that could not otherwise be done.

My invention is not restricted in all details to the presentillustrative embodiment tl'iereof, but is rather defined by the appended claims.

Claims r 1. A mold comprising a plurality of parts sofashioned that when assembled the parts will be unrestrained to move in various directions underthe influence of pressure exerted from within the mold, and means for locking. the, parts together.

2. A mold comprising a plurality of parts so fashioned that when assembled the parts will be free to move under the influence of pressure exerted from within th e mold, and non-mechanical means for locking the parts together.

3-. -flnQ emrr sinss plurality of Parts so fashioned that when assembled the parts willbe freeto move under the influence of pressure exerted from within the mold, and 'electro m'agnetic means for locking the parts together. v V p 4. A mold comprising a plurality of parts so fashioned that whenas'sembled the'pa'rts will be free to move under the influence of pressure exerted from Within-the mold, and electrically 1 ontro1Iedmeans for locking the parts together. I ,7 I

- 5. A "'oll comprising aplurality of 'Inovabl'epart's having smooth adjacent faces and non-mechanical means for locking the parts together. V v y l 6; The method of making castings which consists assembling the mold parts, magnetizing the parts to hold them in position, pur'ing the "casting, and finally demagnetigzing themold "parts to permit free shrinkage of the casting. I

7.- The method of making castings which consistsin assembling the mold parts, passing' an electromagnetic current through the parts to hold them in position, pouring the casting, and thendiscontinuing the electromagnetic current to permit the mold parts to yield under pressure from the casting 8. The method of making castings which consists in first-forming a mold of a plurality of parts, the parts so fashioned that they will be free to move: relative to the casting under "pressure therefrom, next magnetizing the mold parts to hold them together, pouring the casting, and "lastly demagnetizing the mold parts to permit them to 4 accommodate themselves to any movement of the casting.

. 9. A. moldcomprising small particles of mold material, ajbinder therefor, and electro-magnetic means for holding the bound particles together. I

i 10. A multi-part mold having a plurality of segmentalmold parts 2 with'convex sur face areas 8, 9;, 10, 11, and adjacent concave surface areas and non-mechanical means for holding the parts together.

11. A. multi-part segmental mold comprising the mold parts 2, having the convex surface areas 8, 9, 10, 1'1, with concavie surface areas between and connecting said convex surfaceareas, the mold forming, when assembled, the mold chamber 4 with curvilinear extensions 8, 6, of the chamber 4 and open'ingsthereinto and separated from the chamber 4 by the restrictednecks 5, 7.

12. The method of. makinga mold for castings which consists in assembling the mold parts in such relation to each other that each is unrestrained to move bodily under the influence of pressure by the casting while cooling.

13. The method of making a mold for castings which consists in assembling the mold material particles with a binder and locking them with an electromagnetic cur rent.

14:. The method of making a mold for castings which comprises assembling the mold material particles and fashioning the material into mold parts of desired outline, and holding the parts in position by nonmechanical means.

15. The method of making a mold for castings which comprises assembling the mold material particles and fashioning the material into mold parts of'desired outline, and holding the parts in position by an electrical binder.

16. The method of making castings comprising assembling mold parts in desired relation, locking them into such relation by non-mechanical means during the pouring of the casting, and simultaneously unlocking the several mold parts to allow expansion while cooling.

In testimony whereof, I have signed my name to this specification.

THOMAS E.v P. WILSON. 

